1. Technical Field
This invention relates generally to electromechanical speech aids commonly referred to as artificial larynxes and electrolarynxes, and more particularly to an electrolarynx thumbwheel arrangement that helps avoid early thumbwheel component failure.
2. Description of Related Art
Persons without normal use of their vocal cords or larynx often speak with the aid of a prosthetic device called an “electrolarynx.” A typical existing electrolarynx includes a battery-powered electromechanical transducer within a four-inch to five-inch long, cylindrically shaped, electrolarynx case. The transducer vibrates a diaphragm at one end of the case to produce an electrolarynx tone having a fundamental frequency in the speech range of the average human voice.
To speak, the user introduces this artificially generated electrolarynx tone into a resonant speech cavity (i.e., the mouth, nose, or pharynx) by placing the diaphragm end of the electrolarynx case near the resonant speech cavity. The user grasps the case, actuates the ON-OFF switch and the VOLUME control, and then presses the diaphragm end against the outside of their throat so that vibrations travel through the throat tissues and into the mouth and throat. While introducing the electrolarynx tone that way, the user modulates the tone by varying the shape of the resonant speech cavity and by making the usual tongue, teeth, and lip constrictions so as to articulate the modulated tone as human speech.
The VOLUME control of an electrolarynx (or other control circuitry of the electrolarynx) often includes a user-accessible electronic control component called a thumbwheel potentiometer or thumbwheel variable resistor (i.e., a “thumbwheel component”). The thumbwheel component is located in the electrolarynx interior. It includes a wheel that a user turns for purposes of controlling volume, pitch, or some other aspect of the electrolarynx. The wheel has a partially exposed edge extending through a slot in the electrolarynx case in such a way that the user can engage the edge of the wheel from the exterior of the electrolarynx. The user turns the wheel with their thumb or other finger in order to thereby control the volume or other electrolarynx function. The exposed edge of the wheel is as usually knurled to aid the user in that effort.
One concern common to manufacturers, distributors, retailers, and users of such electrolarynxes is early failure of the thumbwheel component. It seems that thumbwheel components as described above often have a much shorter life span than anticipated. They malfunction in one way or another much sooner than desired, with electrolarynx downtime resulting, together with the time and expense of repair and/or replacement, and so a need exits for a way to alleviate that concern.